Recent developments in 3GPP, Third Generation Partnership Project, have introduced enhancements of the functionality for Policy and Charging Control, PCC, for the Evolved Packet System, EPS, to also include volume reporting over the so called Gx interface. This feature is commonly known as Usage Monitoring Control, and the volume referred to could for example be a user's used volume of a certain service or an aggregate of services, measured in, for example, kilobytes,
A fundamental idea behind the Usage Monitoring Control is to provide operators of a system with a tool to monitor and limit bandwidth consumption for users such as, for example, mobile broadband users, on a per user and service basis in order to be able to detect abnormal usage, e.g. so called “bandwidth hogs”, and to also be able to e.g. police the bandwidth after a certain volume limit has been reached by a user. This kind of functionality already exists in some systems for mobile broadband subscription, e.g. traffic is free of charge up to a certain traffic volume per month, following which the user either has to pay an additional fee, or the bandwidth is policed down to a low bit-rate.
In an EPS system, there is a node or function known as the PCRF, Policy and Charging Rules Function, and another node or function known as the PCEF, Policy and Charging Enforcement Function. The PCRF and the PCEF communicate with each other over an interface known as the Gx interface.
The allowed usage, or a “threshold” for allowed usage, is stored in a database that is accessible by the PCRF. When a PDN connection is established to a certain APN, Access Point Name, the user's allowed usage or “threshold” is retrieved from the database by the PCRF at the session establishment, also known as the Gx session establishment. The allowed usage is then provided to the PCEF, Policy and Charging Enforcement Function, usually per so called Monitoring Key. This will then prompt the PCEF to activate usage monitoring for the active PCC rules associated with the Monitoring Key. If a threshold is reached, the PCEF will report this to the PCRF, which may take appropriate action e.g. downgrade the QoS, Quality of Service, or de-activate a certain PCC-rule. The PCRF can also request a usage report from a PCEF for a user prior to a threshold being reached, and can also provide a new threshold value for a user (e.g. for a certain service) to the PCEF.
Document 3GPP TS 23.203 V9.2.0 (2009-09) Technical Specification 3rd Generation Partnership Project; Technical Specification Group Services and System Aspects, Policy and charging control architecture (Release 9) teaches usage monitoring for the accumulated usage of network resources on a per IP-CAN session and user basis, as well as a PCRF that sets and send applicable thresholds to a PCEF for monitoring, and a PCEF that notifies the PCRF when a usage monitoring threshold is reached, and reports the accumulated usage since the last report for usage.